Upgrade to F18, or second LV12R?

Just to throw a wrench into things, I saw on AVSforums, both Brian and Enrico mentioned a paper based 18" driver option that they were investigating which would provide 3dB more output in the upper bass (were you get the "slam" effect) than the current model. At this point, I've seen very little info about this product and it may or may not see the light of day.

HAH! I was just wondering if such a thing existed. I'd expect that paper isn't typically used on such huge woofers, since it's not stiff enough to hold high SPL in low frequencies. Perhaps they would tune it with a frequency response closer to their smaller subs.

If the paper woofer managed to provide 3dB higher output in the upper bass without sacrificing any low end output, that would be impressive. That would put it almost on par (output wise) with the more expensive Funk 18.0.

Ah, the Funk uses a paper / carbon fibre weave, neat. Guessing if Rythmik used a similarly spiffy driver, it would raise costs. Not to mention if they needed to up the amplification.


I'm pretty intrigued by the F18 as it is today. It's overkill for my room size, which might have a chance of quelling my upgradeitis!

I just hope that it doesn't have noticeable disadvantages to the smaller subs (room modes aside).

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Originally Posted by kdaq

Ah, the Funk uses a paper / carbon fibre weave, neat. Guessing if Rythmik used a similarly spiffy driver, it would raise costs. Not to mention if they needed to up the amplification.

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Don't put stock into any one element of subwoofer/speaker design, as performance is a sum of all aspects.

Agreed, Curtis. This is a good segue back to my original question!

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Originally Posted by kdaq

Ah, audio. We all want objective criteria to compare on, but it's never straight-forward what that means in the real world, is it? I suppose that's half the fun. :)

I appreciate the response Enrico! But I must admit, I find myself again a bit hesitant about what the right move is. Cost is a factor, but a clearly superior result would be my priority.

What I find really tricky just reading around, is trying to aggregate and weigh different factors into a real-world end result.


Here's a non-exhaustive list of factors I'm thinking about. In particular, with dual 12" paper cone vented LVX12s vs. a single 18" aluminum cone sealed F18.

Distortion. Reading responses like Brian's discussions of THD vs. other sources of distortion here, it seems to me that distortion modeling is difficult to accurately measure, chart, and interpret. Presumably, all Rythmik subs are as well-optimized as they can be, cost-savings factors aside?

Driver size. All else being equal, smaller drivers should be capable of better transient response, no? I've noticed some discussion around the F8 talking about this, with its 8" drivers. Is this noticeable between a 12" and an 18" driver when playing music at the same (say, moderate) output level, in the same (say, 16-60 Hz) frequency range?

Driver material. All else being equal, paper drivers have less mass than aluminum, and thus are capable of "slightly better dynamics at low to moderate volume levels".

Enclosure type (sealed or vented). On the one hand, "[Rythmik's] recommendation for a subwoofer for music are [their] sealed Direct Servo subwoofers. If your interest is also home theater as well, one or a number of [their] sealed subwoofers will still be an ideal choice. If you are a home theater enthusiast on a modest budget and don’t listen much to music, you might consider one of [their] vented subwoofers.". But on the other hand, "Don't be fooled by typical comments about vented subs lacking accuracy. [Rythmik's vented] subs are tight and musical." So there's a difference. But it's not huge?

Frequency response and masking effect. Perhaps the biggest advantage of bigger subs is lower frequency reproduction. But how often does that matter? "Due to the masking effect, deeper bass will often not be noticeable, unless at very high in amplitude as a special effect. Of course, there is music with high amplitude bass that will mask very low bass." But on the right recording, low response is necessary to capture all ambiance and dynamics. Does the F18 accomplish this noticeably better than dual LVX12s?

Amp type and power output. Rythmik offers class A/B, class H, and class D (Hypex) amps. Not much to say here, as the LVX12 and F18 both use Hypex, and are both sized similarly to their driver size (unlike the LV12R, which uses less power for its size to cut back on cost).

Room modes, etc.. There is no end to discussion around how the room itself affects what we hear, and it's plainly very important (here is a short bit from Rythmik about it). One frequent bit of advice I see is that multiple subs, when placed carefully, can help with evening-out frequency response (room modes) at different points in the room. This is of course not the only factor, but it's an important one.

Perception. Brian makes some good points about this. My experience over the years with trying various headphones and building amp and DAC kits is that I prefer neutral reproduction overall. But do I feel differently about bass reproduction? I want things that may be opposed, like more "slam", but also more room ambiance. One thing I can definitively say is that the LV12R made all other subs I've heard (which includes nice commercial movie theatres, but not much else for home stuff) sound like boomy crap to me, so clearly I value transient response. Maybe I won't know what sub(s) I prefer until I live with them for a bit...

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It all comes down to this: Would a single F18 (or eventually duals) really be noticeably superior to two LVX12s for me?

I have a single LV12R myself. In a 12' by 12' by 8' high sealed room. Mostly HT, but I do listen to some music. I have wondered about the added extension of LVX12 or better yet sealed L12 or L22 with plenty of room gain. Decided I don't need to upgrade since I only have one good spot for sub placement, other spots have much worse response and SQ.

Have you considered dual L22s? They have a tiny footprint, just like L12, but with twice the drivers and power. LV12R is already a tall sub, so L22 should fit in the same spot.

Consider dual:

LVX12s
L22s
E15HPs

Good thought. The L22 is a bit tall for the spot I have though, I need to be able to sit on 'em to get behind my adjacent TV and associated rat nest of wires behind it. :)

Still not sure if I should go LVX12 or F18. For now, just saving up and letting it sit in the back of my mind.

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Originally Posted by kdaq

It all comes down to this: Would a single F18 (or eventually duals) really be noticeably superior to two LVX12s for me?

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In a sealed room with dimensions less than about 60' (that is, the wave length of 20 Hz) in any direction, room modes are a problem. Smaller rooms have more of a problem than bigger rooms. Sealed rooms have more of a problem than open plan spaces. Etc. But for any practical room in any practical house, room modes are a real problem.

So, in general (that is, I'm making generalizations here, so this is not absolute), and IMHO, it's better to have a pair of smaller subs than a single bigger sub. I believe it enough that I put my money where my mouth is and bought a pair of smaller subs. And I'll be darned if it doesn't work just like I hoped it would.

What will work for you? You're the only one who can answer that question. And Rythmik (and other sellers) make that sorta-kinda easy to answer. They give 30 day and 45 day trial periods in your room for the cost of shipping back and forth. A small price to pay maybe for the ability to answer your "two smaller subs or one big one" question definitively.

Disregarding quantity of subs, going to a larger sub is for more output. In the upper bass, the 18 will have quite a bit more output than your 12. Since yours is ported the difference in the low bass will be smaller.

Dual LVX12's are likely to have more output than a single F18 at 20hz. Dual F18 will have more ouput at 20hz and a lot more output at 40hz and above compared to dual LVX12's. Sound quality wise, I'd say there's not much of a difference between the two of them. All the Rythmiks have great sound quality.

So in summary, dual LVX12 will give you more output than what you have now plus smoother frequency response and less bass localization. A single F18 will give you more output, especially in the upper bass than what you have now, but less output at 20hz than dual LVX12 and less smooth response.